--- layout: post title: Logs for the Monero Research Lab Meeting Held on 2019-07-29 summary: Sarang work, Surae work, and miscellaneous tags: [dev diaries, crypto, research] author: el00ruobuob / sarang --- # Logs **\<sarang>** OK, let's begin **\<sarang>** Hello all **\<sarang>** Logs of this meeting will be posted to the GitHub agenda issue afterward **\<sarang>** GREETINGS **\<suraeNoether>** greetings! **\<kenshamir[m]>** hey **\<sarang>** Whoops, here is the current agenda: https://github.com/monero-project/meta/issues/377 **\<sarang>** Let's go ahead with ROUNDTABLE **\<sarang>** I've been working hard on an RCT3 implementation, integrating some nice optimizations and seeing if it's possible to get key images working as expected **\<sarang>** This also led to a bunch of other library updates that the code relies on **\<sarang>** So generally just a lot of coding **\<sarang>** I also gave a fun lecture on the Enigma cipher machine and the math behind it, which is always fun ;) **\<suraeNoether>** nice, what was that for? a meetup or something? **\<sarang>** A friend teaches at a university and thought it would be good for an undergrad crypto class **\<sarang>** Since the Enigma break is all about permutation groups **\<suraeNoether>** nice **\<sarang>** I should be able to finish up an integration of the BP inner product verifier optimization into RCT3 shortly **\<sarang>** Then, of course, DEF CON approaches! **\<suraeNoether>** neat **\<suraeNoether>** i have a very dirty branch on my computer with my matching simulations and experiments being worked upon **\<sarang>** How are those going? **\<hyc>** defcon - anyone got grasshopper repellent? **\<sarang>** -\_\_\_\_- **\<suraeNoether>** i've proven all the theorems necessary to prove that the algorithm in graphtheory.py does what i claim it does, and i'm currently testing that my simulated ledgers are doing what i expect. **\<sarang>** noice **\<sarang>** Will be very neat to see the results, and to see if/how they can work with the analysis that Isthmus et al. are doing on Monero and Zcash **\<suraeNoether>** in addition to that, i have a bunch of MAGIC stuff I need to get done, and my discussions with isthmus' digital forensics work are leaning in that direction **\<suraeNoether>** i'm thinking the content of this project may take up more than two papers :\\ **\<sarang>** Cool! **\<sarang>** Also worth noting that the CLSAG paper has been updated on IACR, thanks mainly to kenshamir[m]'s comments and questions **\<sarang>** kenshamir[m] has also been working on a Rust implementation of CLSAG/MLSAG using the dalek library **\<suraeNoether>** hyc: i hear grasshoppers are delicious, i wonder if any of those fancy vegas michelin star restaurants are capitalizing on the swarm **\<sarang>** Anything you'd like to share on that, kenshamir[m] ? **\<kenshamir[m]>** Hi, the library is finished, not interopable with monero because it uses a different curve though. The numbers are quite impressive and I believe it is due to the way cLSAG was created **\<sarang>** aw shucks **\<sarang>** Will be great to see your MLSAG vs CLSAG numbers at different ring sizes **\<suraeNoether>** i believe there was a question re: ristretto and multi-exp like pippenger right before the meeting that would be relevant here? **\<sarang>** I brought it up a while back because we handle different linear combination sizes \_very\_ differently in the codebase **\<scoobybejesus>** is that rust code in a public repo? **\<sarang>** We use no fewer than 4 methods **\<kenshamir[m]>** The numbers above were for different ring sizes, I may have mis-typed key sizes by accident **\<kenshamir[m]>** 256 and 512 were for the decoy sizes; if I was not clear **\<sarang>** A big part of the reason CLSAG verification is faster than MLSAG is because of the introduction of a new linear combination evaluation algorithm **\<sarang>** kenshamir[m]: can you link them again for the logs? **\<sarang>** (if comfortable having them public) **\<kenshamir[m]>** \<scoobybejesus "is that rust code in a public re"> Not the cLSAG code, once I add documentation and sanitise it I can post it in here **\<sarang>** ty **\<kenshamir[m]>** \<sarang "kenshamir: can you link them aga"> Yep sure **\<scoobybejesus>** :) **\<sarang>** What does "without Pippenger/Straus" mean? Simple iterative evaluation of linear combinations? **\<kenshamir[m]>** Yep exactly **\<sarang>** Impressive numbers **\<sarang>** Of course, it's a different hash function **\<kenshamir[m]>** I just did scalarbase mult in a for loop **\<kenshamir[m]>** haha yeah that too **\<suraeNoether>** hmmmmm **\<sarang>** But if the hash function is the same across both of your CLSAG/MLSAG, then the relative numbers are good **\<suraeNoether>** something that is both faster and smaller and with equivalent security is a no-brainer for implementation (pending audits) **\<sarang>** Speaking of this, still in contact with potential auditors, who are moving very slowly **\<sarang>** Nothing to report on that front :/ **\<suraeNoether>** the improved space allows for a logarithmic increase in verification time without actually slowing down the network (at least when it comes to new nodes downloading the network). judging by these numbers, a ring size of 16 or 32 is no longer like pouring molasses or concrete onto the network **\<sarang>** OK, any other interesting research to report? **\<gingeropolous>** re: audits, or roll-out in general. Is this the kind of thing that could be rolled-out in parallel with existing? i.e., have an overlap, where the network uses the existing as the primary / default, but can optionally use the new thing, and then once new thuing is vetted, just prune the old? **\<hyc>** ^ slow auditors - a lot of people are on summer holiday now **\<gingeropolous>** or, switch to the new and no longer have to relay / verify the old style during the overlap? **\<suraeNoether>** sarang: am i wrong in saying that gingeropolous is correct that clsag could be implemented in parallel before mlsag is deprecated? **\<hyc>** we had a 24hr overlap in the last hardfork for this sort of thing **\<gingeropolous>** this would be kinda different. **\<sarang>** I suppose it could be overlapping, provided the fee model supports it properly **\<sarang>** I don't really see why this would be useful **\<gingeropolous>** i dunno. i'm just opening the conversation regarding the model that all new things need to be audited **\<gingeropolous>** i mean, obvi auditing is great **\<sarang>** yes **\<gingeropolous>** but its not perfect **\<dEBRUYNE>** hyc: Yeah in general, summer constitutes low activity **\<sarang>** It's good for inspiring confidence, as well as the obvious benefits of catching any errors **\<kenshamir[m]>** Can Monero benefit from using bulletproofs for arithmetic circuits? **\<dEBRUYNE>** gingeropolous: Didn't we discuss that kind of model for Bulletproofs or RingCT too? **\<sarang>** Likely not, with our current tx model **\<gingeropolous>** yeah dEBRUYNE **\<sarang>** The scaling isn't great **\<dEBRUYNE>** I think it was shot down for good reasons, but I cannot remember them exactly :-P **\<gingeropolous>** i think that was post audit though **\<sarang>** and we have hash functions, which screw things up **\<sarang>** Zooko had a slide in some presentation where his team estimated the verification time for a circuit with the complexity of Sapling (Sprout? don't recall) **\<sarang>** and BP verification was O(1 s) **\<sarang>** Compared to our current verification time which is probably 1/50th of that **\<sarang>** maybe 1/100th **\<kenshamir[m]>** yikes **\<suraeNoether>** kenshamir: if we designed an arithmetic circuit to describe a ring confidential transaction language, then yes, but that's sort of what RCT3 and omniring and lelantus try to do... sarang, i think zooko was showing "what it would look like for a Sapling transaction language to be proven in the bulletproof setting" not ring confidential transactions, so it's not clear to me whether it'd be slower. **\<suraeNoether>** in our setting **\<suraeNoether>** with the exception of our non-AC-compatible hash function **\<dEBRUYNE>** sarang: That's verification time for fully shielded transactions? **\<suraeNoether>** dEBRUYNE yeah, iirc **\<dEBRUYNE>** Yikes **\<sarang>** Yeah, that timing was just to give an example of what a production-size tx circuit might look like **\<dEBRUYNE>** Especially given that, as far as I know, you have to run a full node in order to properly perform fully shielded transactions **\<dEBRUYNE>** Anyway, I digress :-P **\<sarang>** Anyway, suraeNoether is right in that RCT3 and Omniring try to bring the BP benefits to specific languages used to prove RingCT-type statements **\<sarang>** which is why we're interested in them **\<suraeNoether>** yeah, bulletproofs for use in SNARK-style languages is like... uhm... putting a large-diameter turbofan engine into a Mini Cooper. It's not going to do what you think it's going to do. **\<sarang>** BPs can be much more efficient for languages built for it **\<sarang>** which is why range proofs are so efficient **\<kenshamir[m]>** haha **\<suraeNoether>** indeed **\<suraeNoether>** moving along **\<sarang>** heh **\<sarang>** ok, other research? **\<sarang>** Or QUESTIONS, from the agenda? **\<sarang>** OK then! To ACTION ITEMS **\<sarang>** I'll be finalizing some things for my DEF CON talk, workshop, and panel; and finalizing some RCT3 integration optimizations **\<sarang>** suraeNoether: ? **\<suraeNoether>** oh gosh sorry **\<suraeNoether>** i was computing a number sorry about that. :P **\<sarang>** it's 7 **\<suraeNoether>** my action items are: work on sims and the experimenter, and work with isthmus to formalize statistical hypotheses for testing all this **\<sarang>** Having data from Isthmus's group will be extremely valuable for this kind of analysis **\<suraeNoether>** actually the number is O(153.58\*N), which is the number of bits used to describe the number of possible spend histories at ring size 32 with N outputs. **\<suraeNoether>** which is nutters **\<sarang>** This is all assuming no external information? **\<sarang>** Or other graph-based information on chain reactions and provably-spent outputs? **\<suraeNoether>** merely the total number of self-consistent spend histories **\<sarang>** Ah ok, so for a hypothetical graph **\<suraeNoether>** yeah **\<sarang>** got it **\<gingeropolous>** O(153.58\*N) ... great. now your math is talking in math **\<suraeNoether>** well it means that for, say, 1000 transactions at ring size 32, there are 2^(153,580) possible spend histories. **\<suraeNoether>** anyway **\<suraeNoether>** (N has to be a lot bigger than the ring size for the above formula to hold btw) **\<sarang>** which is... quite reasonable **\<sarang>** Any other final thoughts or questions before we adjourn? **\<sarang>** OK then! Thanks to everyone for participating. We are adjourned